RE: isonic from 10 konts
If you want to focus more on the "clean" feeling of lightwind slalom without the power/size/volume of Formula style equipment , then the iSonic 133 will be a good choice for your weight and sail/wind range, without going to the lightwind extremes of the iS145/155.
iS145/155 will definitely be a more "secure" choice for 10 kts range, but if your 10 kts is "solid" (not patchy) and you've intermediate/advanced skill level, then the extra efficency of the iSonics (c/w Kombat/Carve etc) plus their ability to handle bigger sails/fins effectively will also help get/keep the iS133 going in lighter conditions, while still delivering as active and exciting a ride (slalom feel") as possible for the size/wind range.
A demo or test ride is always a good idea, if possible.
Of course, if you've more questions, please let us know.
Saludos ~ Ian